I took a plan B december 26 and got my period January 9th and it was super heavy and lasted 4-5 days it was on time. Ive had sex 4 times until now but all with condoms and with draw so it was safe. My app said i was suppose to get my period feb 6th and it still has not came yet....should i be worried? Does plan b throw off your cycle? Ive had sore boobs, some acne, slight cramps the week before im scared. Plan b never messed up my cycle before. But maybe because i took 2 within a year.